otsu threshold in python

[azrael]

the otsu filter is a filter that takes a image and from its histogram
calculates the values at which the image should be thresholded to
acomplish an optimal seperation of a foregtround and background
object.
I didn't hear about, but I used it through the ImageJ tool. It gave me
optimal results. I'm working on a project for my clases, and the last
thing I need to accomplish my goal is this filter. Is there anyone who
implemented it.

Thanks Hyuga



On Jun 5, 6:02 pm, Hyuga <hyugaricd... at gmail.com> wrote:
> On Jun 5, 10:19 am, azrael <jura.gro... at gmail.com> wrote:
>
>
>
> > Hy guys.
> > I'd like to ask you for a favour.
> > I tried several times to implement the otsu threshold filter in
> > python. but I failed every time. I found the soucre code i n Java from
> > the ImageJ project but I never worked in Java and there have been used
> > some built in Java functions which I don't know how they behave. I
> > also found the otsu threshold in the ia636 python module and would
> > like only this filter and don't want to import this library.
> > Is there anyone who wold like to help me. I need a function that takes
> > a list of 256 elements as an argument and returns the threshold values
> > for the threshold according to Otsu.
>
> > In addvance, I don't expect someone to do my homework. I really tried
> > it, I have been googling and didn't find a standalone function. I
> > wasn't able write a standalone function because I don't understand the
> > Otsu method. I just know that it works well and that I need it.
>
> > If there is no one that wants to help me with this problem, can
> > someone at least explain me in a detailed way how to implement it.
>
> > Thanks
>
> What is the whole assignment meant to accomplish?  Is the assignment
> to implement the Otsu method?  If so, you shouldn't be trying to find
> library functions.  Or is it just something you need for some larger
> task?
>
> I would ask exactly what problems you're running into, but:
>
> > it, I have been googling and didn't find a standalone function. I
> > wasn't able write a standalone function because I don't understand the
> > Otsu method. I just know that it works well and that I need it.
>
> How do you know you need it?  Did you learn about this in class?  And
> if so, are you expected to understand it?
> I've never even heard of it, but I googled it, and found the fourth
> hit pretty good:http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/MORSE/thresho...
> This gives a reasonable explanation.  I couldn't tell you *exactly*
> why it works, but it's understandable enough from that that I can see
> that it should work, and to see how to implement it.
>
> Not to mention that the above PDF basically *gives* you the
> implementation for free (just make sure not to miss the recurrence
> relations at the end of the section on the Otsu method, or else you'll
> be screwing yourself).
>
> So give that a look and see if it helps.
>
> Hyuga